The present invention relates to a semiconductor device and a manufacturing method thereof. More particularly, it relates to a semiconductor device having a so-called back-side illumination type photoelectric conversion element, and a manufacturing method thereof.
In a CMOS (Complementary Metal Oxide Semiconductor) image sensor including a plurality of photoelectric conversion elements formed therein, miniaturization and densification of the light receiving surface have been pursued. Accordingly, with a related-art so-called front-side illumination type CMOS image sensor to be irradiated with a light on the photoelectric conversion elements from thereabove (the front surface side), unfavorably, the incident light is blocked by the wiring layer over the photoelectric conversion elements, and does not sufficiently reach the photoelectric conversion elements.
Under such circumstances, there have been proposed so-called back-side illumination type CMOS image sensors to be irradiated with a light on photoelectric conversion elements from thereunder (the back surface side) as described in, for example, the following Patent Documents 1 to 7.